On Hideshima Island (Miyako area, Iwate Prefecture, northeast Japan), the Albian Hideshima Formation of the Lower Cretaceous (Aptian to Albian) Miyako Group consists mainly of alternations of turbidite sandstone and mudstone, thick sandstone, and conglomerate. It is also characterized by slump beds and debris flow deposits containing poorly preserved shallow-marine bivalves such as Glycymeris, Eriphyla, Nipponitrigonia, and rudists, representing typical allochthonous occurrences. Eleven genera of the benthic foraminifera have recently been identified in the mudstone of the middle part of the Hideshima Formation. The benthic foraminiferal assemblage is dominated by Bathysiphon spp., Recurvoides spp., and Haplophragmoides spp. Facies analysis and the composition of the benthic foraminifera indicate that the Hideshima Formation accumulated in a slope environment.

The Kaminayoro flora, a late middle to late Miocene megafossil flora, is preserved in the Panke Formation in Shimokawa town, Hokkaido, Japan. It comprises 33 taxa in 14 families and 19 genera, including 1 fern, 3 conifers, and 29 angiosperms (1 monocot and 28 eudicots), comparable with the Mitoku-type flora of middle Miocene to early Pliocene age. Sedimentary facies analysis of the Panke Formation indicates that the depositional setting was mostly fluvial and partly lacustrine. The Kaminayoro flora indicates a vegetation pattern comprising four distinct plant communities: (1) riverside vegetation dominated by Cercidiphyllum crenatum, Acer subcarpinifolium, and Picea sp.; (2) swamp vegetation dominated by Equisetum sp., Bambusioideae gen. et sp. indet., Picea sp., and Salix sp.; (3) lakeside vegetation dominated by Cercidiphyllum crenatum, Salix sp., and Cladrastis chaneyi; and (4) surrounding slope forest vegetation dominated by Fagus palaeojaponica. All four communities are comparable with their modern counterparts in terms of habitat and species composition, indicating that the temperate riparian vegetation of Hokkaido Island was established at least by the late middle to late Miocene.

Paleostress analyses using the three-dimensional orientation distribution of healed microcracks (HCs) in quartz from Cretaceous granitoids have been performed along a ca. 60 km transect normal to the Median Tectonic Line (MTL), central Japan. The paleostress was determined by fitting mixed Bingham distributions to the HC distribution for each sample. As a result, the orientations of the HCs in each data set were grouped into 2–5 clusters, and the group with the maximum density of HCs was regarded as the dominant stress for the data set. The nonparametric correlation coefficients of angular differences of stress for each axis (σ₁, σ₂, and σ₃) were projected onto best-fit great circles on a stereoplot, yielding distances from the MTL of 0.06, 0.09, and 0.43, respectively. The σ₃ axis is orthogonal to the MTL strike in the vicinity of the MTL, but rotates counterclockwise in areas away from the MTL and is roughly parallel to the MTL strike at ca. 60 km from the MTL. The dominant σ₃ axis (NW–SE), which is normal to the MTL in the vicinity of the MTL (southeastern area), is considered to be related to extensional faulting on the MTL at 63–58 Ma (Ichinokawa Phase), whereas the dominant σ₃ axis (NE–SW) parallel to the MTL at a distance from the MTL suggests the influence of the plate convergence direction (NW) at about 75–67 Ma, rather than the influence of MTL-normal extension. The orientations of σ₁ and σ₂ show no correlation with distance from the MTL, indicating that their orientations depend on the local stress state within the granitic body.

We present the mode of occurrence, microfacies, and age of the Kugo Limestone, which occurs as discrete blocks in the Middle Jurassic to earliest Cretaceous Neo mélange in the Kanayama Unit, western Mino Mountains, central Japan. The Kugo Limestone (~80 m thick) consists exclusively of siliceous micrite with common chert nodules. Siliceous micrite dominantly comprises radiolarian lime–mudstone, with lesser thin-shelled bivalve wackestone and packstone and lacks coarse terrigenous grains. These characteristics indicate its deep-marine sedimentation in a pelagic realm of a mid-oceanic region. The conodont biostratigraphy reveals an age of uppermost Carnian to lower Norian. The Kugo Limestone is coeval with, and similar in lithology to, the previously reported Upper Triassic siliceous micrite in mélange units of the Mino belt and neighboring Tamba belt. These units all contain varying amounts of basaltic volcaniclastic sediments including pebble-sized debris within limestone breccia of debris flow facies. Any dissimilarity lies in the lithologic association with bedded chert. In addition, the Mino–Tamba siliceous micrite shows a heteropic relationship with bedded chert of ocean floor facies in coherent units of the Mino–Tamba Belt. The Mino–Tamba siliceous micrite accumulated above and around the carbonate compensation depth (CCD), with underlying bedded chert. The heteropic relationship enables us to construct a sedimentary profile illustrating deposition of the Mino–Tamba siliceous micrite on a low-lying basaltic mound (presumably of hotspot origin) in a deep ocean floor setting where bedded chert accumulated simultaneously. The top of the basaltic mound was above the CCD and was covered by siliceous micrite lacking bedded chert. Siliceous micrite accompanying bedded chert accumulated on the slope of the mound around the CCD, into which limestone and basaltic debris were transported downslope.